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FILES LOD8 and LOD9


flydav
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Hi there,

good question!

Those LOD9 and LOD8 files actually do have a purpose; mesh designers call them "buffer" mesh files.

The FS terrain engine displays terrain mesh data in concentric rings around your aircraft (actually, it's not rings but rather cross-shaped arrangements of rectangular sections), with each ring using less detail. This is similar to mip-mapping in that it avoids using highly detailed data in the mid and far distance that can't be seen anyway; probably conserves system resources too.

Unlike mipmaps, though, the data for the next lower terrain mesh "ring" is not read from the same mesh (the one near the aircraft) but from an available mesh file with the next lower LOD level. Unfortunately, we cannot force FS to use the LOD10 mesh in the distance too, it'll use whatever lower-LOD mesh it finds.

If you don't provide a buffer mesh file then FS will read from one of the default mesh files, which for Europe have a "dismal" resolution of LOD5 (1228 meter grid spacing). Obviously, at that low level of detail the mountains and ridges are more like rolling hills and the distant terrain wouldn't look very good anymore.

Moreover, the difference between the high-res LOD10 mesh in the foreground and low-res LOD5 in the background may lead to light blue "slivers" in the terrain, also referred to as "texture tearing". Those LOD8 and LOD9 buffer mesh files substantially reduce the likelihood of these slivers to show.

Of course, you can experiment yourself by temporarily removing any LOD9, LOD8, or LOD7 mesh you may have for the Alps and then setting up a before/after screenshot comparison. The difference should be obvious.

Hope that answers your question.

Cheers, Holger

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Thanks Holger for such a quick reply!

Now I completely understand why your mesh is either so detailed and fps friendly!

We could call it "Intellimesh"!!! :idea:

Of course now I understand I have to leave all files in their places.

Thanks a lot and hope your gonna keep on working on other cool areas.

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